The attached file describes a problem I had trying to do the video export in 2.2b. I also posted the text at the site listed on the download page, but didn't see a way to post the screenshot there.

As a general note, I made this attempt with two XP machines, neither of which had more than 512M RAM. On both machines, 2.2b ran noticibly slower than 2.0 - however I don't think this error is because of hardware limitations - the error message appeared almost instantly.

According to the error, the program (getWidth function) is not receiving a value where it is expected. Please check in your preferences screen for your video size and try again. You should try this on an empty world just to be sure that it is not a problem with your program.